Semiconductor switching devices having large chip area are provided with gate signal emitters or gate runner structures such as gate pads, gate rings, or gate fingers for transferring an external switching signal provided by external circuitry to an ensemble of switchable cells arranged in an active area of the semiconductor switching device.
Cells located at or in the proximity of an outer rim of the chip area where the gate metallization is located, can receive an external switching signal at a time before the external switching signal can reach switchable cells located in an inner region of the chip area. In particular, if a transient switching signal for a short duration occurs, only those cells close to gate signal emitters are addressed, and thus switched. The cells close to the gate signal emitters must therefore carry the full load current which can result in a current per cell higher than the rated current. Furthermore, this kind of inhomogeneous distribution of the external switching signal across the chip area can prevent the switchable cells from switching concurrently. Simultaneous operation of the switchable cells is thus not ensured and inhomogeneous switching can occur.
In view of the above, there is a need for improvement.